logitech c910 to c920 - worth the upgrade?

I have the c910 now and it produces amazing 1080p videos, but there's a catch. It only does it with the stock Logitech software which, as you might imagine, is very poor. I'm using a third party software to control exposure, gain etc. but there is still 50hz banding at low light levels. Also I records in wmv format which may or may not be the cause of my large file sizes ( about 2gb per 5 mins)